Hitbating aromatic hydrocarbon



?atented dune 5, 1923.

PATENT OFFICE.

STUART 1 'MILLER AND JOHN R. HESS, F PHILADELPHIA, PENNSYLVANIA,

BSSIGNORS TO THE BARRETT COMPANY, A CORPORATION OF NEW JERSEY.

NI'IRA'IING AROMATIC HYDROCARBON.

No Drawing.

To all whom it my concern:

Be it known that we, STUART P. MILLER and JOHN R. Hess, citizens of the United States, residing at Philadelphia, in the 5 county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements 'in Nitrating Aromatic Hydrocarbons, of which the following is a specification.

This invention relates to nitrating aromatic hydrocarbons that are solid at ordinary temperatures. It relates more particularly and will be described in reference to the nitration of naphthalene, though it is '16 not restricted to this particular hydrocarbon.

In some of the well known processes for the production of mono, di-, or tri-nitro naphthalene, the first step is the production of alpha-mono-nitro naphthalene. As

usually accomplished, the nitration of naphthalene, whereby alpha-mono-nitro naphthalene is produced is effected in either of two wa s:

28 (a) The solid naphthalene, which has been previously crushed and ground '15 added to the acid medium, for example, sulfuric'acid, and the nitrifying agent is gradually added to secure nitration, or

30 f(1b) The finely ground solid naphthalene is rst gradually added to the nitrating mixture, the course of nitration bein regulated by the rate of addition of the nap thalene.

In either case the process involves the crushing and grinding of the naphthalene and the handling of it in a solid state, both of which are inconvenient and entail extra labor and expense.

The object of the presentinvention'is to 4.0 reduce the cost of nitrating aromatic hydrocarbons and to render the process more convenient and rapid, while at the same time the process is maintained within the control of the operator and he is enabled to regulate the same in accordance with the results desired. 1

In practici this invention we have discovered that in effecting the nitration of aromatic hydrocarbons which are solid at ordinary temperatures such as naphthalene, fluorene, etc, for example, either by gradually introducing the same into the nitrating mixture or by introducing them Application filed March 8, 1920. Serial No. 364,145.

into sulfuric acid and then gradually adding the nitrating agent, improved and more economical results can be obtained by first meltin the hydrocarbon and then introducing it 1n the molten state into sulfuric acid or the nitrating mixture which is maintained at a sufficiently low temperature so that the hydrocarbon is suddenly cooled and thereby granulated. In accomplishing this ranulation, it has beenfound ve desirab e to violently agitate the cool liquid medium into which the hydrocarbon is being introduced. The granulated hydrocarbon thus produced is easily susceptible to nitration. The extent of this nitration can be controlled in a manner similar to that already well-known by gradually adding the hydrocarbon or by regulating the rate of addition of the nitraiting agent. Some of the advantages gained by this invention are that the crushing and grinding of the solid hydrocarbon and the labor involved in handling it in a solid state are eliminated, thus effecting a very considerable economy in labor and expense by handli the ma terial in a liquid rather thanso 'd form. Also the bringin of the h drocarboirinto the nitrating medium can he more readily controlled; its division in the finely--granulated form in the liquid medium renders it much more susceptible to nitration than in the previous procemes, and the time of offecting the nitration is considerably reduced.

The following is given for illustrative purposes in showi how the invention is carried out with naphthalene, though it is not intended to limit the invention to particular material.

Ten thousand pounds of sulphuric acid of 55.5% strength are introduced into a nitrating wessel. It is cooled to about 40 C. and 5,000 pounds of molten naphthalene at a temperature just above its solidification point is run into the acid while vigorous agitation of said acid is maintained, whereby the naphthalene is granulated. Fort one hundred pounds of 40 B. nitric acid may then be gradually added, while the temperature is maintained at about 40 tb 45 C. until the nitration has progressed to the desired extent. The spent acid is then allowed to settle from the nitrated product '3. The herein described process of nitrating aromatic hydrocarbons solid at normal tom ratures I \YllHl! comprises introducing saiu'hydrocarbons H] a molten state into cool sulfuric acid where granulation takes place and adding a nitrating agent.

4. The herein described process of nitrating naphthalene which comprises introducing liquid naphthaleneinto a cool liquid medium that is used during nitration, whereby said naphthalene is granulated and nitnted. 5. In the recess of nitrating naphthalene the step whlch comprises introducing liquid naphthalene into a cool 1i uid medium .whereby said naphthalene Wlll be granueas es lated, and adding a nitrating agent while said naphthalene remains in said liquid medium,

6. In the process of nitrating naphthalene the step which comprises introducing liquid naphthalene into cool sulfuric acid whereby said naphthalene will be granulated and then adding nitric acid.

7. In the process of nitrating naphthalene the step which comprises introducing liquid naphthalene into cool sulfuric acid whereby said naphthalene will be granulated, and adding a nitrating agent before removal from the sulfuric acid.

8. The herein described process of nitrat ing naphthalene which comprises introduc- .ing hot liquid naphthalene into a cool liquid medium that is used during nitration, while agitating said liquid medium, whereby said naphthalene will be granulated and nitratcd.

9. In the process of nitrating naphthalene, the step which comprises introducing hot liquid naphthalene into cool sulfuric acid while violently agitating said acid, whereby said naphthalene will be granulated and adding a nitrating agent before removal from the sulfuric a -id.

In testimony whereof we affix our signatures.

STUA'RT P. MILLER. JOHN R. HESS. 

